Two outbreaks of Escherichia coli O157:H7 infections in 2006 associated with the consumption of bagged baby spinach and bagged shredded lettuce were collectively responsible for sickening 254 people and causing 3 deaths. Romaine lettuce contaminated with E. coli O157:H7, grown in California, was responsible for causing a multi-state outbreak of 60 infections in 2011. A previous multi-state outb...

A soilborne disease of lettuce, associated with necrosis and dieback, has been found with increasing frequency in California and Arizona over the last 10 years. An isometric virus, serologically related to Tomato bushy stunt virus (TBSV), was consistently isolated from lettuce plants with these disease symptoms. Back-inoculation to healthy lettuce plants and subsequent reisolation of the virus ...

Pyrethrins are nowadays widely used for prevention and control of insects in leaf lettuce. However, there is a concern about the pesticide residue in leaf lettuce. A reliable analytical method for determination of pyrethrins (pyrethrin-and П, cinerin І and П, and jasmolin І and П) in leaf lettuce was developed by using gas chromatography-mass spectrometry (GC-MS). Recoveries of pyrethrins in le...

Plant injury is inherent to the production and processing of fruit and vegetables. The opportunistic colonization of damaged plant tissue by human enteric pathogens may contribute to the occurrence of outbreaks of foodborne illness linked to produce. Escherichia coli O157:H7 (EcO157) responds to physicochemical stresses in cut lettuce and lettuce lysates by upregulation of several stress respon...

The urban area of Dakar, Senegal, contains > 5,000 market-garden wells that provide permanent sites for mosquito larvae, in particular Anopheles arabiensis Patton, the major vector of malaria. A study of the bioecology of mosquito larvae was conducted over 1 yr with a monthly visit to 48 of these wells. Overall, 9,589 larvae were collected of which 80.1% were Culicinae and 11.9% Anophelinae. La...

Internalization of human pathogens, common in many types of fresh produce, is a threat to human health since the internalized pathogens cannot be fully inactivated/removed by washing with water or sanitizers. Given that pathogen internalization can be affected by many environmental factors, this study was conducted to investigate the influence of two types of plant stress on the internalization...

A total of 720 whole, romaine lettuce heads were purchased from retail locations in the Upper Midwest and assessed for coliform and Escherichia coli contamination and for the presence of E. coli O157:H7. During a 16-month period (August 2010 through December 2011), coliform and E. coli counts were enumerated on Petrifilm, and the presence of E. coli O157:H7 and the virulence gene eae was evalua...

Renewed interest in the identification of alternative sources of natural rubber to Hevea brasiliensis has focused on the Compositae family. In our search for Compositae models for rubber synthesis, we extracted latex from stems of two lettuce species: Lactuca serriola, prickly lettuce, and Lactuca sativa cv. Salinas, crisphead lettuce. Both species contained cis-1,4-polyisoprene rubber in the d...

The purpose of this study has been to evaluate the effect of foliar application of PAH organic chemical compounds (anthracene, pyrene) on yield, chemical composition and uptake of nutrients by cv. Vilmorin butterhead lettuce (Lactuca sativa L.). Lettuce was grown under minimum and three-fold higher abundance of substrate in nutrients, as determined according to threshold amounts. A pot trial wa...

The elimination of Listeria monocytogenes inoculated onto a piece of cut iceberg lettuce (3.8 by 3.8 cm) by treatment with chlorinated water (200 micrograms/ml free chlorine) and a 0.5% (wt/vol) solution of FIT Professional Line Antibacterial Cleaner (FIT) was investigated. The efficacy of the two sanitizers was not influenced by the composition of the medium used to culture the L. monocytogene...